If anyone in the world of climate science has the right to say I told you so it may well be -- given. One of the nation's leading environmentalists been given has been -- -- global warming for almost 25 years. And now some of those predictions have come to pass. Supercharged storms and droughts in disappearing Arctic all brought on by the highest temperatures are recorded -- straight. So far of the day he sat down with my co anchor Bill -- for a look at the state of our planet. By the number. They -- just three numbers but taken together they represent a startling new equation for life on this planet as we know it. The first number is two as in two degrees Celsius. That's how much the world's leaders and governments have agreed we -- let the temperature -- and maybe get away with it. The last climate summit in Copenhagen that was literally the only thing everyone could agree the US China Russia Europe even the oil rich Arab emirates. All signed -- to the belief that if the planet warms by more than two degrees. The human race is screwed without even the CEO of Exxon finally admits that hoping carbon into the air warms the planet. Not disputing that. Increasing CO2 emissions and that whispers going to have an impact he'll have a warming impact so the big question is exactly how much can we burn.

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